Alarm notifying system

ABSTRACT

A sound amplification apparatus includes one or more microphones that convert collected sound into an audio signal and transmit the audio signal by radio and a sound receiving apparatus that receives the audio signal transmitted from the microphone and amplifies and outputs the sound based on the audio signal. The sound receiving apparatus is configured to perform sound output control in an emergency mode upon receiving an emergency signal transmitted in response to operation of an emergency switch of the microphone. With this configuration, it is possible to perform appropriate sound control in a dangerous situation such as intrusion of a suspicious person.

RELATED APPLICATION

This application is a continuation application of application Ser. No.13/265,298, filed Oct. 19, 2011, which claims the benefit of JapanesePatent Application No. 2009-105463 filed Apr. 23, 2009, which is anational phase of PCT/JP2010/002611 filed Apr. 9, 2010, the entirecontents of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a sound receiving apparatus thatreceives a sound signal from a microphone and, in particular, relates toa sound receiving apparatus used inside a building such as a classroomof a school, a church, a meeting room, or a hall.

BACKGROUND ART

In recent years, there were several incidents in which a suspiciousperson intruded into, for example, a classroom while students were inclass and killed the students and teachers. Various measures are takenagainst such a crime. Conventionally, there is known an alarm apparatusthat outputs an alarm for informing a security center or the like of,for example, intrusion of a suspicious person.

Patent Literature 1 discloses an alarm apparatus that can identify alocation where an incident occurs and take quick and appropriatemeasures. In the alarm apparatus described in Patent Literature 1, alarmswitches are provided in classrooms and, when the alarm switch isoperated, an emergency signal is transmitted to a broadcasting room. Inthe broadcasting room, a classroom is identified on the basis of theemergency signal. An alarm lamp corresponding to the identifiedclassroom is turned on. Accordingly, it is possible to quickly locate aclassroom in which an incident occurs.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open PublicationNo. 2003-187363

SUMMARY OF INVENTION Technical Problem

In the alarm apparatus described in Patent Literature 1, the alarmswitch is provided in a predetermined location of the classroom. Whenneither a student nor a teacher is present near the alarm switch, it isdifficult to press the alarm switch without being noticed by anintruder. If the act of moving to the location where the alarm switch isinstalled and pressing the alarm switch is exposed to the eyes of theintruder, the teacher and students may be exposed to increased danger.

In particular, inside a building, when an educational material is playedin the classroom using a sound amplification apparatus or other audioequipment, because of sound emitted by the sound amplification apparatusor the audio equipment, it is difficult to distinguish, from the outsideof the classroom, an abnormal state from an ordinary state of the class.There is a risk that damage increases because of a delay in takingmeasures. There is also a risk that the intruder is driven todistraction because of amplified sound offensive to the ears of theintruder. It is also likely that disorder is caused because it isdifficult for victims to communicate with one another.

In view of the background, it is an object of the present invention toprovide a sound receiving apparatus that, in a dangerous situation suchas intrusion of a suspicious person, can perform appropriate soundcontrol and notify the dangerous situation.

Solution to Problem

A sound receiving apparatus according to the present invention is asound receiving apparatus that receives an audio signal transmitted fromone or more microphones, which convert collected sound into an audiosignal and transmit the audio signal by radio, and amplifies and outputssound based on the audio signal, the sound receiving apparatusperforming sound output control in an emergency mode when receiving anemergency signal transmitted in response to operation of an emergencyswitch of the microphone. The sound receiving apparatus comprises adetecting section that detects a sound signal including a tone signalencoded as the emergency signal and an emergency signal detectingsection that extracts the tone signal from the sound signal detected bythe detecting section and detects the emergency signal from theextracted tone signal.

Advantageous Effect of Invention

According to the present invention, since the sound receiving apparatusreceives an emergency signal transmitted according to the operation ofthe emergency switch included in the microphone, which somebody oftenhas at hand, there is an excellent effect that it is possible to switchthe sound receiving apparatus to the sound output control in theemergency mode without being noticed by an intruder.

As explained below, other forms are present in the present invention.Therefore, the disclosure of the present invention intends to provide apart of the present invention and does not intend to limit a scope ofthe invention described and claimed herein.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing the configuration of a sound receivingsystem according to a first embodiment.

FIG. 2 is a diagram showing the configuration of a microphone.

FIG. 3 is a diagram showing a detailed configuration of a soundprocessing section.

FIG. 4 is a flowchart for explaining the operation of a soundamplification apparatus in a normal state.

FIG. 5 is a flowchart for explaining the operation of the soundamplification apparatus performed when an emergency switch is operated.

FIG. 6 is a flowchart for explaining the operation of the soundamplification apparatus performed when the emergency switch is operated.

FIG. 7 is a diagram showing the configuration of a sound receivingsystem according to a second embodiment.

FIG. 8 is a flowchart for explaining the operation of the soundamplification apparatus performed when the emergency switch is operated.

DESCRIPTION OF EMBODIMENTS

Sound receiving systems and sound receiving apparatuses according toembodiments of the present invention are explained below with referenceto the drawings. The embodiments explained below are mere examples ofthe present invention. The present invention can be modified to variousforms. Therefore, specific configurations and functions disclosed belowdo not limit the scope of claims. In the following explanation, a soundreceiving apparatus used in a classroom of a school is explained.However, the sound receiving apparatus can be used not only in theclassroom of the school but also in a church, a meeting room, a hall,and the like.

First Embodiment

FIG. 1 is a diagram showing the configuration of a sound receivingsystem 1 according to a first embodiment. The sound receiving system 1according to the first embodiment comprises a sound amplificationapparatus 10 used in each of plural classrooms CR (Classroom) and amanagement apparatus 40 connected to plural sound amplificationapparatuses 10.

The sound amplification apparatus 10 comprises a sound receivingapparatus 13 that receives audio signals transmitted from pluralmicrophones 11 a and 11 b by radio and amplifies and outputs sound basedon the received audio signals. In the following explanation, the pluralmicrophones 11 a and 11 b are generally referred to as “microphone 11”.

An emergency switch 12 is provided in the microphone 11. When theemergency switch 12 is operated, the microphone 11 transmits anemergency signal by radio while including the emergency signal in a tonesignal. The emergency signal is a signal for requesting the soundreceiving apparatus 13 to perform sound output control in an emergencymode. The emergency mode is a mode for relatively increasing the volumeof collected sound of the microphone 11 with respect to the volume of anaudio signal, which hinders emergency notification, and outputting soundhaving high audibility of the collected sound. Specific sound outputcontrol in the emergency mode is explained later.

The emergency switch 12 may be a dedicated switch or may be commonlyused with switches having other functions provided in the microphone 11in advance such as a function switch. When the function switch is used,the microphone 11 may be configured to transmit an emergency signal, forexample, when the function switch is pressed long for a predeterminedtime (e.g., two seconds) or more.

As the microphone 11, a normal hand-held microphone 11 a, a microphone11 b of a type that can be used freehand while being hung from the neck,or the like can be used. In this embodiment, two microphones 11 areshown. However, it goes without saying that the number of microphones 11is not limited to two.

FIG. 2 is a diagram showing the configuration of the microphone 11. Themicrophone 11 comprises a built-in microphone 61 that collects sound andconverts the sound into an audio signal, an external apparatus audiosignal input section 62 to which an audio signal of an externalapparatus is input, an external microphone sound input section 63 towhich sound of an external microphone is input, and a sound inputswitching section 64 that switches an audio signal output from collectedor input audio signals. The microphone 11 comprises a tone encoder 65that encodes a tone signal on the basis of inputs from the emergencyswitch 12, other switches which are not shown, and the like, a tonesignal generating section 66 that generates a tone signal, a mixingsection 67 that mixes the tone signal and the audio signal output fromthe sound input switching section 64, an FM modulation section 68 thatFM-modulates the mixed audio signal, and an amplifier 69.

The signal indicating that the emergency switch 12 is operated is inputto the sound input switching section 64 as well. The sound inputswitching section 64 performs switching of sound according to the signalfrom the emergency switch 12. For example, while sound of the microphone11 is muted, a signal input from the emergency switch 12 forces thesound input switching section 64 to release the mute. For example, whilean external apparatus audio signal is being input, a signal input fromthe emergency switch 12 forces the sound input switching section 64 toswitch the external apparatus audio signal to a built-in microphone orexternal microphone sound input. By performing such switching, it ispossible to collect sound from the microphone 11 in an emergency. It ispossible to communicate a state in the classroom to the outside bysound.

Infrared communication is used to transmit an audio signal from themicrophone 11 to the sound receiving apparatus 13. An infrared ray isblocked by the wall of the classroom CR and does not leak to theoutside. Therefore, when the infrared communication is used, advantagesare that the communication may not interfere with the soundamplification apparatus 10 in the adjacent classroom CR; the samemicrophone 11 can be used in the adjacent classroom CR; and leakage ofsound information is very small. In this embodiment, an example in whichthe infrared communication is used is explained. However, short distanceradio such as Bluetooth (registered trademark) may be used.

The sound receiving apparatus 13 comprises plural light receptionsensors 14 that receive infrared signals transmitted from the pluralmicrophones 11, a sound processing section 15 that processes an audiosignal, and a speaker 20 that outputs sound. The light reception sensors14 are capable of communication with the plural microphones 11 havingdifferent channels. On the ceiling or the like, there are installed anumber of light reception sensors 14 necessary to cover the entireclassroom according to a range of infrared rays of the microphones 11.The sound processing section 15 comprises a DVD input terminal 16 and aTV input terminal 17 that receive audio signals from a DVD (DVD videoaudio reproducing apparatus) 31 and a TV (television) 32. The soundprocessing section 15 comprises a relay output terminal 18 that outputsan emergency signal and a line output terminal 19 that outputs an audiosignal. The relay terminal 18 switches ON and OFF when the relayterminal 18 detects an emergency mode. After being ON or OFF for apredetermined time, the relay terminal 18 turns OFF or ON. Instead of ONand OFF at a relay contact, ON and OFF signals may be output by atransistor or the like.

FIG. 3 is a diagram showing a specific configuration of the soundprocessing section 15. The sound processing section 15 comprises an FMdetection circuit 21 that FM (frequency modulation)—detects a waveformacquired by the light reception sensor 14 and acquires an audio signal,a band-pass filter (BPF) 22 that extracts a sound signal (20 Hz to 20kHz) from the acquired audio signal, and a band-pass filter (BPF) 23that extracts a tone signal (32.768 kHz). The tone signal is a signalused for suppressing audible noise specific to an FM modulation systemand sound output from jamming signals that occur when the microphone 11is not powered or when a reception radio wave is weak. The tone signalis a signal transmitted on the audio signal. The tone signal ismodulated by an encoded emergency signal, whereby the emergency signalis transmitted. As a frequency of the tone signal, it is also possibleto use a frequency between 60 Hz and 80 Hz and a frequency between 15kHz and 90 kHz besides the frequency explained above. If a frequency of100 Hz to 20 kHz is used for the former case and that of 20 Hz to 14 kHzis used for the latter case as the sound signal, it is possible toprevent the tone signal from being mixed into the sound signal.

The sound processing section 15 comprises a mixer 24 that adds up theextracted sound signal and a sound signal from the DVD 31 or the TV 32.An output of the mixer 24 is connected to the speaker 20 via a variableamplifier 29 and connected to the line output terminal 19 via anothervariable amplifier 30.

The sound processing section 15 comprises a tone decoder 25 that decodesa tone signal extracted from an FM-demodulated signal by the band-passfilter 23. A signal (an emergency signal) decoded by the tone decoder 25is input to an emergency signal detecting section 26 and a displaysection 27.

When the emergency signal detecting section 26 detects the emergencysignal, the emergency signal detecting section 26 transmits theemergency signal to the management apparatus 40 from the relay outputterminal 18 and inputs a signal indicating that the emergency signal isdetected to the mixer 24 and the variable amplifiers 29 and 30. When themixer 24 detects the emergency signal, the mixer 24 suppresses thevolume of the DVD 31 or the TV 32. The variable amplifier 29 suppressesvolume output from the speaker 20. The variable amplifier 30 amplifies aline-output sound signal. The speaker 20 may be built in the soundreceiving apparatus 13 or may be installed in an appropriate location inthe classroom as a separate speaker.

The display section 27 turns on an LED 28 on the basis of the inputsignal. In FIG. 3, only one tone decoder 25, one emergency signaldetecting section 26, and one display section 27 are drawn. However,actually, the sound processing section 15 comprises tone decoders 25,emergency signal detecting sections 26, and display sections 27equivalent to the number of at least one microphone (2 ch) that generateemergency signals.

Referring back to FIG. 1, the configuration of the management apparatus40 is explained. The management apparatus 40 comprises a mixer 41, aspeaker 42, and an emergency lamp 43. The mixer 41 has a function ofprocessing a sound signal received from the sound receiving apparatus 13and outputting sound from the speaker 42. The mixer 41 has a function ofturning on the emergency lamp 43 upon receiving an emergency signal fromthe sound receiving apparatus 13. Emergency lamps 43, which are equal tothe number of the classrooms CR, may be arranged to represent apositional relation of the classrooms CR. Upon receiving the emergencysignal, the mixer 41 may turn on the emergency lamp 43 corresponding tothe sound receiving apparatus 13 at a reception source. Accordingly, itis possible to easily locate a classroom CR in which an emergencyoccurs. The mixer 41 of the management apparatus 40 is connected to aspeaker for public address system 44 provided in each of the classroomsCR.

The operation of the sound amplification apparatus 10 according to thisembodiment is explained. First, the operation of the sound amplificationapparatus 10 in a normal state is explained and then an operationperformed when the emergency switch 12 operated is explained.

FIG. 4 is a flowchart for explaining the operation of the soundamplification apparatus 10 in the normal state. The microphone 11collects sound (S10) and converts the sound into an audio signal (S12).The microphone 11 transmits the audio signal to the sound receivingapparatus 13 (S14).

The sound receiving apparatus 13 receives input of an auxiliary audiosignal from the DVD 31 or the TV 32 (S16). The sound receiving apparatus13 receives the audio signal transmitted from the microphone 11 (S18)and adds up the received audio signal and the auxiliary audio signalwith the mixer 24 (S20). Subsequently, the sound receiving apparatus 13outputs sound based on the added-up audio signal from the speaker 20(S22). In FIG. 4, for convenience of explanation, the input of theauxiliary audio signal (S16) and the reception of the audio signal (S18)are described in this order. However, actually, audio signals arecontinuously input from the DVD 31 or the TV 32, which is an auxiliarysound source, and the sound receiving apparatus 13 continuously receivesaudio signals from the microphone 11.

FIG. 5 is a flowchart for explaining the operation of the soundamplification apparatus 10 performed when the emergency switch 12 isoperated. When detecting that the emergency switch 12 is operated in themicrophone 11 during the normal operation shown in FIG. 4 (S30), themicrophone 11 transmits an emergency signal to the sound receivingapparatus 13 (S32). Upon receiving the emergency signal (S34), the soundreceiving apparatus 13 suppresses the volume of the auxiliary audiosignal from the DVD 31 or the TV 32 (S36).

Consequently, other sound in the classroom CR is not blocked by thesound of the DVD 31 or the TV 32. Therefore, utterance content of anintruder and utterance content of a teacher can be easily heard. In stepS36, the volume of the auxiliary audio signal may be reduced to zero ormay be simply reduced. If the volume of the auxiliary audio signal isreduced to zero just at the moment when an intruder intrudes, it islikely that the intruder becomes aware that some emergency processing isperformed. Therefore, sound of another sound source may be continuouslyoutput at volume smaller than usual.

Once the emergency switch 12 is turned on, the emergency signal to thesound receiving apparatus 13 is continuously transmitted. However, theemergency mode on the microphone 11 side is released and changes to thenormal mode according to power on and off of the microphone 11. Thetransmission of the emergency signal is stopped. When once receiving theemergency signal, the sound receiving apparatus 13 maintains theemergency mode. However, upon receiving a sound signal without theemergency signal from the microphone 11 that returns to the normal modeor the microphone 11 operating in the other normal mode, the soundreceiving apparatus 13 returns to a state previous to the emergencymode. Consequently, volume settings of the sound receiving apparatus 13return to setting immediately before the sound receiving apparatus 13changes to the emergency mode.

FIG. 6 is a flowchart for explaining another operation of the soundamplification apparatus 10 performed when the emergency switch 12 isoperated. When detecting that the emergency switch 12 is operated in themicrophone 11 (S30), the microphone 11 transmits an emergency signal tothe sound receiving apparatus 13 (S32). Upon receiving the emergencysignal (S34), the sound receiving apparatus 13 suppresses the volume ofan audio signal from the microphone 11 (S38) and transmits the emergencysignal and the audio signal to the management apparatus 40 located in aremote location (S40). The sound receiving apparatus 13 may control thevolume of audio signals from the plural microphones 11 in associationwith the microphone 11 at a transmission source of the emergency signal.

Upon receiving the emergency signal (S42), the management apparatus 40turns on the emergency lamp 43 (S44) and outputs the received audiosignal from the speaker 42 (S46). The management apparatus 40 informs,through emergency broadcast from the speaker for public address system44, that an emergency has occurred (S48). The management apparatus 40may use the received audio signal for this emergency broadcast. Themanagement apparatus 40 does not perform the emergency broadcast for theclassroom CR where the sound receiving apparatus 13 at a transmissionsource of the emergency signal is provided and the classrooms CR aroundthe classroom CR. The emergency broadcast is not heard in a space wherethe microphone 11 is located and a space where the sound receivingapparatus 13 is provided. Even if the emergency broadcast is transmittedto these spaces as a sound wave, volume in these spaces only has to besmaller than the volume of the emergency broadcast for the classroomsaround the spaces and have low audibility enough for making itimpossible to understand contents of the broadcast. Accordingly, it ispossible to prevent the emergency broadcast from uselessly exciting theintruder.

With the operation shown in FIG. 6, since the volume output from thespeaker 20 decreases, it is possible to effectively prevent echo andhowling that occur because the microphone 11 picks up the sound from thespeaker 20. Therefore, it is possible to transmit high-quality sound tothe management apparatus 40.

In the above explanation, the operations of the sound amplificationapparatus 10 are explained separately with reference to FIGS. 5 and 6.However, the sound amplification apparatus 10 may perform both theoperation shown in FIG. 5 and the operation shown in FIG. 6.

Second Embodiment

FIG. 7 is a diagram showing the configurations of a sound receivingsystem 2 and the sound amplification apparatus 10 according to a secondembodiment. Basic configurations of the sound receiving system 2 and thesound amplification apparatus 10 according to the second embodiment arethe same as those in the first embodiment. However, the secondembodiment is different from the first embodiment in that a camera 33 isconnected to the sound amplification apparatus 10. In the secondembodiment, instead of directly connecting the sound receiving apparatus13 and the management apparatus 40, the management apparatus 40 isconnected to the sound receiving apparatus 13 through a network from thecamera 33. The configuration of the camera 33 is explained below.

The camera 33 comprises an image pickup section 34 with a zoom functionthat picks up an image of a state in the classroom CR, a sound inputinterface 35 connected to the line output terminal 19 of the soundprocessing section 15, and a contact input interface 36 connected to therelay output terminal 18 of the sound processing section 15. The camera33 comprises a multiplexer (MUX) 37. The multiplexer 37 superimposes animage picked up by the image pickup section 34, a sound signal inputfrom the sound input interface 35, and an emergency signal input fromthe contact input interface 36. The camera 33 comprises a networkinterface 38 that transmits a signal superimposed by the multiplexer 37to the network.

The network interface 38 of the camera 33 is connected to the Internet52 via a gateway 51. Therefore, the camera 33 can transmit thesuperimposed signal to, for example, a security company and a municipaloffice by designating an appropriate address as a destination. Thenetwork interface 38 is connected to the management apparatus 40 as wellvia the gateway 51. The signal from the camera 33 is input to a PC 45 ofthe management apparatus 40 via a hub 53 and input to the mixer 41 viathe hub 53 and a network interface 46. The PC 45 may be providedindependently from the management apparatus 40.

The operations of the sound amplification apparatus 10 according to thesecond embodiment are explained below. The operation of the soundamplification apparatus 10 according to the second embodiment in thenormal state is the same as that in the first embodiment (see FIG. 4).In the second embodiment, as in the first embodiment, the soundamplification apparatus 10 performs an operation for suppressing thevolume of an auxiliary audio signal (see FIG. 5) and an operation forsuppressing an audio signal from the microphone 11 (see FIG. 6). In thesecond embodiment, unlike the first embodiment, the sound amplificationapparatus 10 transmits an audio signal and an emergency signal to thenetwork via the camera 33. Therefore, this operation will be explained.

FIG. 8 is a flowchart for explaining the operation of the soundamplification apparatus 10 according to the second embodiment. Whendetecting that the emergency switch 12 is operated (S50), the microphone11 transmits an emergency signal to the sound receiving apparatus 13(S52). Upon receiving the emergency signal (S54), the sound receivingapparatus 13 transmits the emergency signal and an audio signal to thecamera 33 (S56).

The camera 33 always picks up an image of a state in the classroom CR(S58). Upon receiving the emergency signal and the audio signaltransmitted from the sound receiving apparatus 13 (S60), the camera 33superimposes the emergency signal and the audio signal and a videopicked up by the camera 33 (S62) and transmits a superimposed signalobtained by the superimposition to the network (S64). The managementapparatus 40 receives the superimposed signal. The mixer 41 reproducesthe emergency signal and the audio signal. The PC 45 reproduces thevideo. The PC 45 may reproduce, in addition to the video, at least oneof the emergency signal and the audio signal. The transmission andreception of the superimposed signal can be performed by an electronicmail text, attachment, or streaming but is not limited to these.

According to this embodiment, it is possible to provide more detailedinformation to the outside by transmitting and receiving a video inaddition to sound in the classroom CR. The video may be a moving imageor at least one or more still images. Since the information istransmitted through the network, it is possible to transmit theinformation not only to the management apparatus 40 but also to anappropriate destination. Upon receiving the emergency signal, the camera33 may be able to pick up images of every corner of the classroom byzooming out to an angle larger than a zoom angle at that point.

Other Embodiments

Other embodiments of the present invention are explained below.

A sound receiving apparatus according to an embodiment is a soundreceiving apparatus that receives an audio signal transmitted from oneor more microphones, which convert collected sound into an audio signaland transmit the audio signal by radio, and amplifies and outputs soundbased on the audio signal. The sound receiving apparatus is configuredto perform sound output control in an emergency mode upon receiving anemergency signal transmitted in response to operation of an emergencyswitch of the microphone.

With this configuration, since the sound receiving apparatus receivesthe emergency signal transmitted according to the operation of theemergency switch included in the microphone, which somebody often has athand, it is possible to switch the sound receiving apparatus to thesound output control in the emergency mode without being noticed by anintruder.

A sound receiving apparatus according to an embodiment comprises areceiving section that receives an audio signal and an emergency signalfrom the microphone, an input section to which an auxiliary audio signalis input from a sound source different from the microphone, a volumeadjusting section that adjusts the volume of the audio signal from themicrophone and the auxiliary audio signal, and an output section thatoutputs sound based on the audio signal and the auxiliary audio signal.The volume adjusting section is configured to suppress the volume of theauxiliary audio signal in the emergency mode.

With this configuration, since the volume of the unnecessary auxiliarysound source is suppressed in an emergency, other sounds can be easilyheard. It is possible to notify, without being hindered by the auxiliarysound source such as another acoustic apparatus, a dangerous situationrecognized by sound collected by the microphone.

A sound receiving apparatus according to an embodiment comprises areceiving section that receives an audio signal and an emergency signalfrom the microphone, a volume adjusting section that adjusts the volumeof the audio signal received from the microphone, an output section thatoutputs sound based on the audio signal, and a signal output sectionthat outputs the audio signal for a remote location. The volumeadjusting section is configured to suppress, in the emergency mode, thevolume of an audio signal output to a speaker.

With this configuration, since sound amplification in the microphone issuppressed, the microphone does not collect again sound output from thespeaker. Echo due to sound reflection in a room and howling in the caseof approach to the speaker of the microphone less easily occur.Therefore, it is possible to output an audio signal having highaudibility to a remote location.

In the sound receiving apparatus according to the embodiment, the volumeadjusting section is configured to increase, in the emergency mode, thevolume of the audio signal output to the signal output section.

With this configuration, it is possible to appropriately output theaudio signal to a remote location.

In the sound receiving apparatus according to the embodiment, the soundadjusting section is configured to increases or decreases, in theemergency mode, the volume of an audio signal from the microphone thatreceives the emergency signal among the plural microphones and thevolume of audio signals from the other microphones, both in the samedirection.

With this configuration, it is possible to control, in the emergencymode, the volume of the other microphones in association with themicrophone that transmits the emergency signal.

In the sound receiving apparatus according to the embodiment, the volumeadjusting section is configured to increases or decreases, in theemergency mode, the volume of an audio signal from the microphone thatreceives the emergency signal among the plural microphones and thevolume of audio signals from the other microphones, in oppositedirection.

With this configuration, it is possible to control, in the emergencymode, the volume of the other microphones in association with themicrophone that transmits the emergency signal.

A sound receiving apparatus according to an embodiment has an electriccontact for outputting the emergency signal to the outside in responseto reception of the emergency signal.

With this configuration, it is possible to control an externalelectronic apparatus according to the emergency signal.

A sound receiving apparatus according to an embodiment is configured totransmit the emergency signal to a network in response to reception ofthe emergency signal.

With this configuration, it is possible to notify an apparatus connectedto the network of the emergency signal.

A sound processing method according to an embodiment is a soundprocessing method by a sound receiving apparatus that receives, byradio, an audio signal transmitted from a microphone, receives anauxiliary audio signal from a sound source different from themicrophone, amplifies sound based on the audio signal and the auxiliaryaudio signal, and outputs the sound from a speaker. The sound processingmethod comprises a step of the sound receiving apparatus receiving anemergency signal from the microphone, a step of the sound receivingapparatus adjusting the volume of the audio signal from the microphoneand the auxiliary audio signal, the sound receiving apparatussuppressing the volume of the auxiliary audio signal upon receiving theemergency signal, and a step of the sound receiving apparatus outputtingthe sound based on the audio signal and the auxiliary audio signal fromthe speaker.

With this configuration, since the volume of the unnecessary auxiliarysound source is suppressed in an emergency, other sounds can be easilyheard. It is possible to notify, without being hindered by the auxiliarysound source such as another acoustic apparatus, a dangerous situationrecognized by sound collected by the microphone.

A sound processing method according to an embodiment is a soundprocessing method by a sound receiving apparatus that receives, byradio, an audio signal transmitted from a microphone, amplifies soundbased on the audio signal, and outputs the sound from a speaker. Thesound processing method comprises a step of the sound receivingapparatus receiving an emergency signal from the microphone, a step ofthe sound receiving apparatus suppressing the volume of an audio signaloutput from the speaker upon receiving the emergency signal, and a stepof the sound receiving apparatus outputting the audio signal for aremote location upon receiving the emergency signal.

With this configuration, since sound amplification in the microphone issuppressed, the microphone does not collect again sound output from thespeaker. Echo due to sound reflection in a room and howling in the caseof approach to the speaker of the microphone less easily occur.Therefore, it is possible to output an audio signal having highaudibility to a remote location.

A program according to an embodiment is a program for receiving, byradio, an audio signal transmitted from a microphone, receiving anauxiliary audio signal from a sound source different from themicrophone, amplifying sound based on the audio signal and the auxiliaryaudio signal, and outputting the sound from a speaker. The program has aconfiguration for causing a computer included in a sound receivingapparatus to execute a step of receiving an emergency signal from themicrophone, a step of adjusting the volume of the audio signal from themicrophone and the auxiliary audio signal, the step of suppressing thevolume of the auxiliary audio signal when the sound receiving apparatusreceives the emergency signal, and a step of outputting the sound basedon the audio signal and the auxiliary audio signal from the speaker.

With this configuration, since the volume of the unnecessary auxiliarysound source is suppressed in an emergency, other sounds can be easilyheard. It is possible to notify, without being hindered by the auxiliarysound source such as another acoustic apparatus, a dangerous situationrecognized by sound collected by the microphone.

A program according to another embodiment is a program for receiving, byradio, an audio signal transmitted from a microphone, amplifying soundbased on the audio signal, and outputting the sound from a speaker. Theprogram has a configuration for causing a computer included in a soundreceiving apparatus to execute a step of receiving an emergency signalfrom the microphone, a step of suppressing, when the sound receivingapparatus receives the emergency signal, the volume of an audio signaloutput from the speaker, and a step of outputting the audio signal for aremote location when the sound receiving apparatus receives theemergency signal.

With this configuration, since sound amplification in the microphone issuppressed, the microphone does not collect again sound output from thespeaker. Echo due to sound reflection in a room and howling in the caseof approach to the speaker of the microphone less easily occur.Therefore, it is possible to output an audio signal having highaudibility to a remote location.

A sound receiving system according to an embodiment comprises themicrophone and the sound receiving apparatus. The sound receivingapparatus is configured to receive the audio signal and an emergencysignal corresponding to operation of an emergency switch of themicrophone from the microphone.

With this configuration, it is possible to output the audio signal fromthe microphone to a remote location in response to reception of theemergency signal. Therefore, it is possible to grasp, in the remotelocation, a state in an emergency.

In the sound receiving system according to the embodiment, the soundreceiving system has a configuration for outputting sound at inaudiblevolume in a space where the sound receiving apparatus is provided.

With this configuration, it is possible to prevent an intruder fromnoticing that the audio signal is transmitted to an apparatus present ina location different from the space where the sound receiving apparatusis provided.

A sound receiving system according to an embodiment comprises themicrophone, the sound receiving apparatus, and a camera that picks up animage of a space including the microphone. The sound receiving apparatusinputs the audio signal and an emergency signal to the camera in theemergency mode. The camera is configured to transmit the audio signal,the emergency signal, and an image picked up by the camera to a network.

With this configuration, it is possible to transmit the image picked upby the camera together with the audio signal from the microphone.

The sound receiving system and the sound receiving apparatus accordingto the present invention are explained in detail above with reference tothe embodiments. However, the present invention is not limited to theembodiments.

In the embodiments, the first embodiment in which the relay outputterminal 18, the line output terminal 19, and the management apparatus40 are directly connected and the second embodiment in which the relayoutput terminal 18, the line output terminal 19, and the managementapparatus 40 are connected to the network via the camera 33 areexplained as separate embodiments. However, it is also possible tocombine the two embodiments. For example, in the second embodiment, thecamera 33 may receive an emergency signal from the sound receivingapparatus 13, superimpose the emergency signal and a picked-up video,and transmit a superimposed signal to the network. When a built-inmicrophone or an external microphone is provided in the camera 33, thecamera 33 may superimpose an audio signal obtained by the built-inmicrophone or the external microphone and the emergency signal, andtransmit a superimposed signal to the network. Further, as explainedabove, the camera 33 may superimpose the emergency signal and a videosignal and transmit a superimposed signal to the network and transmit anoutput signal of the sound receiving apparatus 13 to the network as anaudio signal.

In the embodiments, the example in which the variable amplifier 29suppresses volume output from the speaker 20 in the emergency mode isexplained. However, the sound receiving apparatus 13 or the microphone11 may increase the volume of the microphone 11 (the volume of a soundinput of the built-in microphone or the external microphone) in responseto operation of the emergency switch 12. Accordingly, sound of themicrophone 11 can be easily heard in the space where the microphone 11is located.

In the embodiments, the example in which the configuration of the soundprocessing section 15 is configured by the circuit is explained.However, the sound processing section 15 can be configured by softwareas well. A program for causing a computer (a control section) includedin the sound receiving apparatus 13 to execute the steps of theoperations shown in FIGS. 4 to 6 or FIG. 8 is also included in the scopeof the present invention.

The preferred embodiments of the present invention conceivable atpresent are explained above. However, various modifications are possiblefor the embodiments. It is intended that the appended claims include allsuch modifications that are within the true spirit and the scope of thepresent invention.

INDUSTRIAL APPLICABILITY

As explained above, according to the present invention, since the soundreceiving apparatus receives an emergency signal transmitted in responseto operation of the emergency switch included in the microphone, whichsomebody often has at hand, there is an excellent effect that it ispossible to switch the sound receiving apparatus to the sound outputcontrol in the emergency mode without being noticed by an intruder. Thesound receiving apparatus is useful as a sound amplification apparatusor the like used inside a building such as a classroom of a school, achurch, a meeting room, or a hall.

REFERENCE SIGNS LIST

-   1, 2 sound receiving systems-   10 sound amplification apparatus-   11 microphone-   12 emergency switch-   13 sound receiving apparatus-   14 light reception sensor-   15 sound processing section-   16 DVD input terminal-   17 TV input terminal-   18 relay output terminal-   19 line output terminal-   20 speaker-   21 FM detection circuit-   22, 23 band-pass filters-   24 mixer-   25 tone decoder-   26 emergency signal detecting section-   27 display section-   28 LED-   29, 30 variable amplifiers-   31 DVD-   32 TV-   33 camera-   34 image pickup section-   35 sound input interface-   36 contact input interface-   37 multiplexer-   38 network interface-   40 management apparatus-   41 mixer-   42 speaker-   43 emergency lamp-   44 speaker for public address system-   45 PC-   46 network interface-   51 gateway-   52 Internet-   53 hub-   61 built-in microphone-   62 external apparatus audio signal input section-   63 external microphone sound input section-   64 sound input switching section-   65 tone encoder-   66 tone signal generating section-   67 mixing section-   68 FM modulation section-   69 amplifier

1. An alarm notifying system that is used inside a building, the alarmnotifying system comprising: a camera that picks up an image of apredetermined area in the building, the camera being connected to anetwork; and a terminal device that communicates with the camera, theterminal device having an emergency switch and transmitting an emergencysignal to the camera in response to operation of the emergency whereinthe camera transmits the emergency signal and the image to the networkwhen the camera receives the emergency signal from the terminal device.2. The alarm notifying system according to the claim 1, wherein theterminal device is a microphone and transmits an audio signal capturedby the microphone to the camera, and wherein the camera transmits theaudio signal to the network with the emergency signal and the image. 3.The alarm notifying system according to claim 2, wherein the camerasuperimposes the image, the audio signal and the emergency signal andtransmits a superimposed signal to the network.
 4. The alarm notifyingsystem according to claim 1, wherein the camera continuously picks upthe image of the predetermined area.